Interpretive Summary: Advances in agricultural technology have led to the development of active sensors that can detect the amount of light reflected from plants as an indicator of plant health. This study investigated the potential usefulness of the Holland Scientific ACS 470 active sensor that is specially designed to provide its own illumination and measure reflectance in the red, red-edge, and near infrared portions of the electromagetic spectrum. Using the red and red-edge information, the sensor gave improved performance over conventional sensing in detecting stress in Scotts pine seedlings. This study shows that the ACS 470 sensor has the potential to detect stress in a nursery setting. Improvements could be made to adapt the sensor to sensing stress from a moving overhead irrigation boom in a nursery.